The present disclosure relates to a method for designing a lens of a lighting device, and more particularly, to a method for designing a lens that is capable of determining a light irradiation area of a lighting device to refract light toward the determined irradiation area.
Recently, LEDs have been increasingly adopted as light sources to save energy in many industries including lighting devices. Accordingly, studies for effectively and efficiently using LEDs in industrial fields are being actively conducted.
However, the LED light source has a property of light travelling in a straight line. Thus, as illustrated in FIG. 1, an emission shape of light energy of an LED that is similar to a point light source has a light distribution characteristic in which light is concentrated into a central portion rather than surrounding portions. To supplement a dazzling phenomenon due to the light concentration and drawbacks of the pollution, optical lenses for diffusing and adjusting the LED light distribution are being developed.
Also, a lighting device using the LED as a light source has to be designed so that a light irradiation area changes according to an installed position of the lighting device. For example, it is necessary to design the lighting device so that an irradiation area (i.e., an irradiation surface) of light emitted from the LED changes according to installation places and purposes, such as locations of general streetlamps, security lights, and lights for tunnels.
Also, it is required to efficiently design and install lighting devices so that irradiation surfaces between the lighting devices adjacent to each other do not overlap each other.